1. Field of the Invention
A damper assembly for damping oscillations of a component of a vehicle suspension.
2. Description of the Prior Art
The damper assemblies of the type to which the subject invention pertains attach to a vehicle frame and to a suspension component for damping effects of the vehicle traveling over uneven terrain and control the motion of the component in relation to the vehicle frame. One such damper assembly is illustrated in US2002/0027051 to Grundei on Mar. 7, 2002 wherein a first tube has a generally tubular shape that defines an inner surface. The first tube extends along an axis from an open upper portion to a closed lower portion to define a fluid chamber containing a damping fluid. A rod extends axially between a first end exteriorly of the first tube and a second end interiorly of the first tube. A guide is annularly disposed about the rod and engages the upper portion of the first tube for aligning the rod and sealing the damping fluid in the first tube. A piston defines a plurality of openings and is attached to the second end of the rod and is slidably disposed in the first tube. The piston is moveable toward the upper portion of the first tube in a rebound stroke and is moveable toward the lower portion of the first tube in a compression stroke. A valve seat is disposed in the first tube and extends radially outwardly from the axis. A first spring is disposed in the first tube and engages and extends axially away from the valve seat. A valve body is annularly disposed about the axis in the first tube adjacent to the first spring. The valve body has a periphery and a top and a bottom and defines a plurality of bores extending axially through the valve body from the top to the bottom. A second spring is disposed in the first tube and extends axially away from the top of the valve body toward the upper portion of the first tube. A bumper is disposed in the first tube and engages the second spring for compressing the second spring as the bumper moves axially in the first tube toward the lower portion of the first tube. However, the valve bodies of such damper assemblies inherently affect the damping force provided by the damper assembly over the entire stroke of the piston within the first tube and therefore may be more difficult to tune and obtain the most desirable damping characteristics for a given damper assembly application.
Damping forces provided by damper assemblies are primarily dependent upon two factors, the speed of the piston and rod and the amount of travel of the rod and piston. The damping force generated by prior art damping assemblies is only related to the speed of the rod and piston. It would thus be desirable to provide a solution which includes a damper assembly in which operation of the valve body is more tunable and is dependent on the position of the rod and piston in the first tube.
Additionally, other prior art damper assemblies may include jounce cushions disposed at one or both ends of the first tube for extreme movement of the piston within the first tube. These cushions slow or stop the movement of the piston at the end of its stroke and absorb energy and shock associated with this movement. For example, a jounce cushion may be attached to the guide to slow or stop the movement of the piston at the end of the rebound stroke. While it is important to prevent contact by the piston at the end of the compression stroke or the rebound stroke, these cushions are not ideal for safety and durability of the damper assembly. Therefore, there remains a need for a damper assembly that provides a more durable solution to slowing or stopping piston movement at the end of its stroke.